title: EEG changes measured by spectrum analysis under hyperbaric conditions.
abstract: The EEG activity was followed during simulated diving to 20 m depth. Altogether 49 EEG records of 5 min length were taken in 5 divers breathing compressed air in a close system. No significant changes of the EEG could be found during either compression or decompression if only conventional indicators, such as the amplitude of theta activity, were tested. However, a complex "normality ratio," based on multivariate analysis of a normal material, was capable of showing significant impairment of the brain activity during the decompression. The indicator has been designed to reflect the abnormality level rather than the short-lasting EEG changes, the latter being mostly dependent on the alertness fluctuations. The EEG changes associated with alertness fluctuations were assessed separately by means of a specific "alertness indicator" and a prominent alertness increase was found during both compression and decompression phases of the diving experiment.
authors.affiliation: Maritime and Tropical Medicine Institute, Gdynia, Poland.
authors.forename: R
authors.initials: R
authors.lastname: Dolmierski
authors.forename: J
authors.initials: J
authors.lastname: Maslowski
authors.forename: M
authors.initials: M
authors.lastname: Matousek
authors.forename: I
authors.initials: I
authors.lastname: Petersen
mesh_terms: D000328:Adult; D003664:Decompression; D004242:Diving; D004569:Electroencephalography / Q000379:methods*; D006801:Humans; D006931:Hyperbaric Oxygenation